Artificial hand and wrist assembly



Feb. 4, 1941. F. v. EBERLE ARTIFICIAL HAND AND WRIST ASSEMBLY Filed June 26, 1939 2 Sheets-Sheet l INVENTOR 5, M ffiek/e BY J4 P ATTORNEY Feb. 4, 1941. F. VIEBERLE 2,230,378

ARTIFICIAL HAND AND WRIST ASSEMBLY Filed June 26. 1939 2 Sheets-Sheet 2 INVENTOR l i k ME'er/e ATTORNEY Patented Feb. 4, 1941 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to artificial limbs and more particularly to an improved hand and wrist assembly. The primary purpose of the invention is to provide an artificial hand which is I5 rugged and reasonably simple and economical to manufacture and also to provide the novel hand and wrist assembly.

Figure 1 represents a side elevation of the improved hand and wrist assembly embodying the invention.

Figure 2 represents a top elevation of the device shown in Figure 1 with a portion thereof cut away so that the parts located within the interior of the hand shell may be seen.

Figure 3 is a cross-sectional view taken on line 3-3 of Figure 2.

Figure 4 is a cross-sectional view taken on line 44 of Figure 2.

Figure 5 is a fragmentary cross-sectional view illustrating the relative positions of the parts of the locking device when in operative or looking position.

Figure 6 is a cross-sectional view taken on line 66 of Figure 2.

Referring to the drawings, I represents a hand and a portion of a wrist. The hand comprises a hollow or shell member II open at the back, which opening is closed by a cover plate I2 which may be fixedly or removably secured to the member II in any appropriate manner.

I prefer that it be removably secured to member I I in the event that one desires to make any adjustments of the moving parts located in member II. The front part of the body II has an opening therein into which extend the knuckle portions of four fingers I3, I4, I and I6. The knuckle portions of the four fingers may be integral with each other and the fingers proper may be spaced from each other as shown. Extending through an elongated opening in said knuckles and secured to the sides of member I I at the front portion thereof is a shaft I! about which said fingers may be pivotally swung or rotated in unison. Integral with said knuckle portions and depending therefrom is a projection or boss I8 to which is secured an extension I9. At the front part of the member II there is a projecting portion which has a slot therein hollow member I I at a place near said slot. Extension 8 is secured to projection 9.

In order that the hand may be disposed at an angle to the vertical axis thereof, there is provided a supporting member 22 having a concave recess in which is located the convex side of the lower end of the hand and wrist assembly member I I.

At the center of said member 22 are upstanding spaced members 23 and 24 integral with member 22 and extending into the large opening in the lower end of member II. A pair of aligned pivotal pins 25 are mounted in the lower end of the member II and extend within the opening thereof and said pins 25 extend through openings in said members 23 and 24 whereby the member 22 can be rotated with respect to member II and about said pins as an axis. A coiled tension spring 26 has one end thereof secured to the interior of hollow member II and 20 its other end secured to a projecting member 21 anchored to member 23. This spring 26 normally tends to rotate said member II about the pins 25 and dispose said member II at an angle to member 22. In order that the member II 25 may be maintained in such a position that its longitudinal axis is coincident with the axis of the support 22, and also so that the member II may be locked in its angular position, the support 22 is provided with a plurality of openings 30 adapted to accommodate a pin 28 located in an opening in the lower part of member I I and normally forced outwardly by spring 29. The pin 28 has a short pin 39 with a knob extending through a bayonet slot in the side of the them- 35 ber at the lower end thereof. In operation when it is desired to change the angular position of the hand, the pin 35 is moved upwardly to remove pin 23 against the action of spring 25 out of the opening in member 22 and it is rotated into 40 the small opening of the bayonet slot where it remains.

The member II is moved with respect to member 22 and the pin 30 is pushed out of the upper end of the bayonet slot and the spring 29 auto- 45 matically forces pin 28 into the opening in support 22 located therebelow.

Integral with the member II and secured thereto at the inner surface thereof is a boss 3i to which is secured a pivot or axis 32. Mounted 50 on the outer part of axis 32 is a V-shaped actuator 33 through whose apex extends axis 32. The V-shaped actuator comprises a pair of arms 34 and 35 located in approximately the same plane as projection I9. A link 33 is loosely piv- 55 oted to the end of arm 34 and projection I9, and a link 31 is loosely pivoted to the end of arm 35 and the projection 8 so that upon actuation of the V-shaped actuator the links 36 and 31 are simultaneously actuated to move simultaneously said finger assembly and thumb towards or away from each other depending upon the direction of movement of the V actuator, controlled by to and fro movement of a rigid element 38 extending through support 22 and into member II. Also mounted on said axis 32 is a toothed segment 39 having teeth 40 in its outer periphery, extending towards the upper part of member II. Located between segment 39 and V actuator is a thick disc 4I integral with said segment and actuator and eccentrically mounted on axis 32 whereby said disc 4I and segment 39 are actuated in unison with the V actuator.

In order that the fingers and thumbs may be locked in position and especially so that a very firm grip may be provided between the ends of the first two fingers and the end of the thumb which have rubber or other resilient inner .tips 42 which are adapted to meet each other, I provide the locking mechanism which is so firm that a sheet of paper located between the thumb and two first fingers may be held so tightly that when locked, the paper cannot be removed therefrom without tearing the same. Independently actuable and pivotally mounted on axis 32 is a member 43 having integral therewith a stop arm 44. A locking member toothed pawl 44 is pivotally mounted on the outer end of member 43 and is in the same plane as the segment. The lower edge of member 44 is close to and in contour complementary to the outer edge of segment 39, with teeth 45 extending in a direction opposite to teeth of segment 39. A tension spring 46 has one end anchored to the upper part of hollow member I I and its other end secured to the member 44 and normally tends to rotate the member 44 in a direction away from the segment 39. A boss 41 is located rearwardly of boss 3| and is integral with member I I. Pivotally mounted on boss 41 is an L shaped actuator 48, one end of which extends through a slot in the palm of member II, and its other end is loosely pivoted on one end of a link 49 whose other end is loosely pivoted on the pawl 44. The actuator 48 is pivotally mounted on the boss 41 at one end of the small arm of said L member.

In operation the spring 46 pulls the pawl 44 out of engagement with the segment 39 and the arm 44 downwardly a small distance until it bears against the inner part of shell II whereupon the fingers I3, I4, I and I6 may be moved towards or away from thumb 29 depending on the direction of application of force to the actuating member 38.

Assuming that the user desires to grip an article, the element 38 is pulled in a direction away from the member I I and in so doing the V actuator acting through the links 36 and 31 actuates the thumb and fingers towards each other to grip that article. It is obvious that since the member 38 is ordinarily actuated by a muscle of the shoulder or arm that only a small degree of force may be exerted between the fingers and thumb and therefore objects of any considerable weight cannot be normally held between the fingers and thumb even if they are locked in the position to which they have been actuated by movement of member 38. When the locking mechanism herein disclosed is actuated, it first brings the fingers and thumb closer together and then locks them in this new position. Upon actuation of the L shaped member 48 the same is rotated about its pivot and pulls the link 49 downwardly and rearwardly and pulls the pawl 44 downwardly whereupon its teeth intermesh with the teeth of segment, and it also pulls the stop upwardly and against the action of spring 46 whereupon the segment actuates the V actuator which through links 36 and 31 brings the fingers and thumb closer together.

When the lock arm 48 reaches its upper degree of travel, the link 49 and arm are either in dead center or to that side of dead center where there is a strong locking of the fingers and thumb which cannot be disturbed-except upon downward movement of said arm.

Although the invention has been described in detail, it is not to be limited to the exact construction shown, because it is subject to modifications and changes within its scope.

I claim:

1. An artificial hand comprising a body member, a plurality of fingers and a thumb pivotally mounted on said body-member, an axis secured to said body member, a V actuator mounted at its apex on said axis, links pivotally mounted at the ends of said V actuator and connected to said fingers and thumb, means for rotating said V actuator on said axis to move said fingers relative to said thumb, a toothed segment pivotally mounted on said axis and connected to said V actuator for simultaneous rotation therewith, means, other than said first means, for actuating said V actuator to move said fingers relative to said thumb and to lock said fingers and thumb in position, said second means including a pivoted toothed member adapted to be moved into and out of engagement with said segment, a finger actuable link pivoted to said body member and extending through an opening therein and a link connecting said toothed member and said finger actuable link to said toothed member.

2. An artificial hand comprising a body member, a plurality of fingers and a thumb pivotally mounted on said body member, an axis secured tosaid body member, a V actuator mounted at its apex on said axis, links pivotally mounted at the ends of said V actuator and connected to said fingers and thumb, means for rotating said V actuator on said axis to move said fingers relative to said thumb, a toothed segment pivotally mounted on said axis and connected to said V actuator for simultaneous rotation therewith, a stop link pivotally mounted on said axis, a toothed element pivotally connected to said stop link between the ends of said stop link, a finger actuable link pivotally mounted on said body member and extending through an opening therein, a link pivotally connected to said finger actuable link and said toothed member, resilient means tending to swing said toothed member away from said segment and ,tomaintain said stop link against said body, said finger actuable link adapted to swing said toothed member into engagement with said segment, to act against said spring and to rotate said segment and V actuator and to, automatically lock itself against accidental release.

FRANK V. EBERLE. 

